silva

I just picked up a B6 1.8T that runs rough. I managed to drive it from Utah to Ontario, Canada (1800 miles) without issues, but, there is a problem.

At idle, there is a tremendous amount of negative pressure in the crankcase (vacuum). It is hard to remove the oil cap off of the valve cover. The same goes for the oil dipstick. Also, power is lacking severely, which I figure is a result of this issue.

Through searching, I have found that the Suction Jet pump is a common failure, but in all the reading, it seems as though the symptoms of a failed suction jet pump is POSITIVE pressure in the crankcase. I did not find a thread with the symptoms I have (NEGATIVE pressure).

The issue is technically simple, really. There is either a defective valve in the system somewhere that is allowing the intake manifold to "suck" all the air out of the crankcase at all times, or there is a blockage in the intake before the throttle body. The later is unlikely, as I am able to drive the car at speed without many issues, albeit under reduced power.

Any suggestions before I get in to it? Its always nice to have help with diagnosis. TIA.

tonyj

Find someone to pull codes. THe issue is likey something else than crancase pressure.

diagnosticator1

The rough running symptom may be related to the fault causing the excessive neg crankcase pressure, but I don't think it's the direct cause. There is supposed to be negitive crankcase pressure, a few inches water columb, but not enough to hold the cap and the dip stick in place. The crankcase pressure goes slightly positve when boost exists.

silva

I had already pulled codes, just misfires and a Positive Pressure deviation code. Fixed now!

silva

This particular valve is spring loaded such that it will only open during decelleration (higher vacuum condition), and is otherwise closed (Idle, part Throttle, WOT). This is only one of many PCV valves on the 1.8T, but it is definately one that makes the car run like crap when it becomes faulty.

There is a small plunger within this valve, with the spring pressure keeping it closed. Somehow, this little plunger turned itself sideways within the bore, therefore defeating the purpose of the valve.

Of course, in ETKA, the part looks nothing like the real thing. It is shown as two separate parts (A T-fitting, and a valve), when in fact it is only one piece.

Here is a picture in case anyone has this problem in the future:

<img src="http://pictureposter.audiworld.com/40679/etka_pcv_valve.jpg">

diagnosticator1

illistation number "20". The pressure regulator limits the maximum negitive crankcase pressure while allowing any positive pressure to vent freely into the intake after the MAF meter. The PCV or "bleeder valve, limits flow into the intake manifold when the intake manifold vacuum exists, and closes for boost conditions when manifold pressure is above ambient air pressure. Regarding the configuration difference noted, the following item is the same part according to the VIN split shown. Later versions of the crankcase ventilation setup have the PCV, or bleeder valve oriented vertically, connected to the oil filter base directly. Your VIN is &gt; 8E-4-000001, right?

Thanks for the update!